This invention relates to apparatus for realtime fast reconstruction and display of dose distribution, which is used for calculating the distribution in a patient's body of the absorbed dose of radiation, displaying the results of the calculation in the form of isodose curves, and determining the optimum conditions of radiation, thereby aiding in drawing an effective radiotherapeutic plan for the particular patient.
For radiotherapy, it is important that the radiation should be applied to a patient's body in such a manner that only a tumor and its immediate vicinity is allowed to absorb a required dose of radiation and the remaining healthy tissues are not caused to absorb any appreciable dose of radiation. For this purpose, various radiotherapeutic instruments are devised so as to provide a variety of radiation techniques adaptable by the operation of a host of parameters to thereby meet all conceivable positions and shapes of tumor to be treated. To this end, devices for the optimization (realtime fast reconstruction and display) of dose distribution are used. Such a device for realtime fast reconstruction and display of dosage distribution is disclosed in U.S. Pat. No. 3,871,579. Since this device is designed to determine an effective radiation technique by series calculations making full use of various parameters, the first round of calculation performed on the therapeutic condition takes up some time. Besides, the device requires a relatively long time period for optimization and therefor requires several rounds of such calculation. In addition, this device has disadvantages that it has no capacity for memorizing the optimum conditions concerning the parameters of all the therapeutic instruments involved and it is incapable of reflecting individual hospital policies undeterminable by realtime fast reconstruction and delicately variant rules of prescriptions observed by individual physicians. A variety of highly advanced therapeutic techniques have made appearance recently. Some of them call for far more fast reconstructions than have heretofore been used. Performance of so many fast reconstructions inevitably demands choice of preference between rapidity of reconstruction and accuracy of reconstruction. Thus, the device has inevitably to sacrifice one of the two preferences.